@laveritalondon- Not sure why this is happening on the posts page (where I checked). I suggest disabling pagination and then enabling it on that collection list. Publish and test.
If it does not resolve it, I would open a trouble ticket with Webflow.
It looks like you have a base tag (<base>: The Document Base URL element - HTML: HyperText Markup Language | MDN) set on your site (under advanced settings in the “Custom Code” tab of site settings) which has really narrow use cases and can break lots of features like this. Is it possible to remove the base tag?